1 Field of the Invention
The present invention relates to a liquid crystal display and, more particularly, to a liquid crystal display with a PenTile pixel arrangement for displaying high resolution images.
2 Description of the Related Art
Generally, a liquid crystal display (LCD) includes two panels with electrodes for generating electric fields, and a liquid crystal layer sandwiched between the two panels. Different voltages are applied to the electrodes to form electric fields, which re-orients the liquid crystal molecules in the liquid crystal layer to control the light transmittance, thereby displaying the desired images.
The LCD includes a plurality of pixels with pixel electrodes and red, green and blue color filters. The pixels are driven by signals transmitted thereto via signal wires. The signal wires include scanning signal lines or gate lines for carrying scanning signals, and image signal lines or data lines for carrying image signals. A thin film transistor (TFT) connected to one gate line and one data line are formed at each pixel. The TFT controls the image signals transmitted to the pixel electrode provided in the pixel.
There are several types of arrangements for the red, green and blue color filters at the respective pixels. Among them are a stripe type where the color filters of the same color are arranged along the respective pixel columns, a mosaic type where the red, green and blue color filters are sequentially arranged in row and column directions, and a delta type where the pixels are arranged in zigzags in the column direction, and the red, green and blue color filters are sequentially arranged in the pixels. In the case of the delta type, the three unit pixels with the red, green and blue color filters form one dot, which closely express a circle or a diagonal line on the display screen.
The ClairVoyante Laboratories has proposed a pixel arrangement called the “PenTile Matrix™,” which is advantageous in displaying high resolution images while gives minimized design cost. In the pixel arrangement, the blue unit pixel is common to two dots, and the neighboring blue pixels receive the data signals from one data driving IC while being driven by two different gate driving ICs. With the use of the PenTile Matrix pixel arrangements the resolution of the ultra extended graphics array (UXGA) level can be realized by way of a display device of the super video graphics array (SVGA) level. Furthermore, the number of relatively expensive data driving ICs is decreased although the number of relatively cheap gate driving ICs is increased. This minimizes the production cost for the display device.
However, in the above-described LCD, the blue pixel has a shape of a diamond and correspondingly, the signal lines for carrying the data signals are elongated. Consequently, the signal delay of the data signals to be transmitted to the pixels becomes severe such that the display characteristic becomes non-uniform. Therefore, it is difficult to apply the PenTile Matrix pixel arrangement to large LCDs. Furthermore, a blue pixel enclosed by the red and green pixels occupies two pixel columns and the blue pixel differs in size from the red or green pixel, which makes it very difficult to form a storage capacitor required for the LCD.
The data lines for transmitting data signals to the red or green pixels or two gate signal lines become close to each other so that the signal lines is liable to be short-circuited to reduce the production yield and the intervention of the neighboring data lines deteriorates the display characteristic. Furthermore, since the neighboring blue pixels are driven by one driving IC, the data driving ICs are required to be provided at both sides of the display area. Therefore, the display device becomes enlarged and it becomes difficult to form repair lines for repairing disconnection and short circuit at the periphery of the display area. The inversion for preventing the deterioration of the liquid crystal gives irregular polarity to the red, green and blue pixels to generate flicker and to differentiate the brightness of the pixel columns, thereby deteriorating the image quality of the display device.
Meanwhile, in order to increase the resolution, the LCD having a PenTile Matrix pixel arrangement utilizes rendering.